diff options
Diffstat (limited to 'js/src/vm/ProxyObject.h')
-rw-r--r-- | js/src/vm/ProxyObject.h | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/js/src/vm/ProxyObject.h b/js/src/vm/ProxyObject.h new file mode 100644 index 000000000..a0a929b20 --- /dev/null +++ b/js/src/vm/ProxyObject.h @@ -0,0 +1,145 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- + * vim: set ts=8 sts=4 et sw=4 tw=99: + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#ifndef vm_ProxyObject_h +#define vm_ProxyObject_h + +#include "js/Proxy.h" +#include "vm/ShapedObject.h" + +namespace js { + +/** + * This is the base class for the various kinds of proxy objects. It's never + * instantiated. + * + * Proxy objects use ShapedObject::shape_ primarily to record flags. Property + * information, &c. is all dynamically computed. + */ +class ProxyObject : public ShapedObject +{ + // GetProxyDataLayout computes the address of this field. + detail::ProxyDataLayout data; + + void static_asserts() { + static_assert(sizeof(ProxyObject) == sizeof(JSObject_Slots0), + "proxy object size must match GC thing size"); + static_assert(offsetof(ProxyObject, data) == detail::ProxyDataOffset, + "proxy object layout must match shadow interface"); + } + + public: + static ProxyObject* New(JSContext* cx, const BaseProxyHandler* handler, HandleValue priv, + TaggedProto proto_, const ProxyOptions& options); + + const Value& private_() { + return GetProxyPrivate(this); + } + + void setCrossCompartmentPrivate(const Value& priv); + void setSameCompartmentPrivate(const Value& priv); + + GCPtrValue* slotOfPrivate() { + return reinterpret_cast<GCPtrValue*>(&detail::GetProxyDataLayout(this)->values->privateSlot); + } + + JSObject* target() const { + return const_cast<ProxyObject*>(this)->private_().toObjectOrNull(); + } + + const BaseProxyHandler* handler() const { + return GetProxyHandler(const_cast<ProxyObject*>(this)); + } + + void setHandler(const BaseProxyHandler* handler) { + SetProxyHandler(this, handler); + } + + static size_t offsetOfValues() { + return offsetof(ProxyObject, data.values); + } + static size_t offsetOfHandler() { + return offsetof(ProxyObject, data.handler); + } + static size_t offsetOfExtraSlotInValues(size_t slot) { + MOZ_ASSERT(slot < detail::PROXY_EXTRA_SLOTS); + return offsetof(detail::ProxyValueArray, extraSlots) + slot * sizeof(Value); + } + + const Value& extra(size_t n) const { + return GetProxyExtra(const_cast<ProxyObject*>(this), n); + } + + void setExtra(size_t n, const Value& extra) { + SetProxyExtra(this, n, extra); + } + + gc::AllocKind allocKindForTenure() const; + static size_t objectMovedDuringMinorGC(TenuringTracer* trc, JSObject* dst, JSObject* src); + + private: + GCPtrValue* slotOfExtra(size_t n) { + MOZ_ASSERT(n < detail::PROXY_EXTRA_SLOTS); + return reinterpret_cast<GCPtrValue*>(&detail::GetProxyDataLayout(this)->values->extraSlots[n]); + } + + static bool isValidProxyClass(const Class* clasp) { + // Since we can take classes from the outside, make sure that they + // are "sane". They have to quack enough like proxies for us to belive + // they should be treated as such. + + // proxy_Trace is just a trivial wrapper around ProxyObject::trace for + // friend api exposure. + + // Proxy classes are not allowed to have call or construct hooks directly. Their + // callability is instead decided by handler()->isCallable(). + return clasp->isProxy() && + clasp->isTrace(proxy_Trace) && + !clasp->getCall() && !clasp->getConstruct(); + } + + public: + static unsigned grayLinkExtraSlot(JSObject* obj); + + void renew(JSContext* cx, const BaseProxyHandler* handler, const Value& priv); + + static void trace(JSTracer* trc, JSObject* obj); + + void nuke(); + + // There is no class_ member to force specialization of JSObject::is<T>(). + // The implementation in JSObject is incorrect for proxies since it doesn't + // take account of the handler type. + static const Class proxyClass; +}; + +inline bool +IsProxyClass(const Class* clasp) +{ + return clasp->isProxy(); +} + +bool IsDerivedProxyObject(const JSObject* obj, const js::BaseProxyHandler* handler); + +} // namespace js + +template<> +inline bool +JSObject::is<js::ProxyObject>() const +{ + // Note: this method is implemented in terms of the IsProxy() friend API + // functions to ensure the implementations are tied together. + // Note 2: this specialization isn't used for subclasses of ProxyObject + // which must supply their own implementation. + return js::IsProxy(const_cast<JSObject*>(this)); +} + +inline bool +js::IsDerivedProxyObject(const JSObject* obj, const js::BaseProxyHandler* handler) { + return obj->is<js::ProxyObject>() && obj->as<js::ProxyObject>().handler() == handler; +} + +#endif /* vm_ProxyObject_h */ |